This application will address the major unanswered questions in the clinical epidemiology of coronary artery disease (CAD) among blacks. If funded the present application will extend by two years the findings of previous work in the following areas: (a) Natural history. An emerging body of data suggests that blacks with symptomatic CAD have a worse prognosis than do whites. Additional observation in the cohort of 1,800 patients enrolled will yield definitive information on the survival experience of low-income, urban blacks with all the important CAD syndromes. A cohort of 356 blacks are being following after hospital discharge for myocardial infarction (MI); 1,233 black patients are being followed after cardiae catheterization for suspected CAD; and 247 patients are being followed after coronary bypass grafting (CABG) surgery. (b) The health eare seeking behavior of lower socio-economic blacks attending a public hospital will be compared to middle class blacks and whites seeking care at a large HMO. Prehospital delay with acute MI will serve as the index event. Collection of psychosocial data will permit an examination of the effect of psychological and social class factors separate from institutional barriers. (c) Prior reports suggest that black women are more susceptible to CAD and have worse survival among symptomatic cases. The extensive data base available will allow a detailed analysis of this question. (d) Recovery after CABG will be evaluated through vital status surveillance, repeat treadmill exercise testing and survey questionnaire. Determinants of survival in this cohort will be evaluated to possible establish mechanisms for the high death rate. Particular emphasis will be directed toward the effects of left ventricular hypertrophy (LVH). As an important sequela of long- standing hypertension, LVH is more common in blacks and may account for much of the reduction in survival. As estimated by echocardiogram the presence of LVH is a more powerful predictor of mortality than the severity of CAD or the state or left ventricular function. A cohort of 678 patients are being followed after catheterization and echo measurement of LV mass. The role of LVH on survival following MI will also be examined. In 4 groups, stratified by the presence or absence of LVH and the presence or absence of CAD, the prevalence of ventricular arrhythmias will be determined (75/group). These data will provide information on the independent contribution of LVH to ventricular arrhythmias and allow an assessment of its quantitative relationship.